Sewing rings or suturing members are used to attach heart valve prostheses to heart tissue. Sutures connect the sewing ring to the tissue. The sewing rings are made of biologically inert materials that are compatible with blood and heart tissue. Many sewing rings have fabric covers which permit tissue ingrowth whereby the sewing rings are firmly attached to the heart tissue. The tissue ingrowth does not allow the sewing ring to be readily removed from the heart tissue without cutting additional heart tissue. Examples of suturing members for heart valves are shown in U.S. Pat. Nos. 3,099,016; 3,491,376; and 3,763,548.
Prosthetic heart valves have been proposed which are attached to the heart tissue with clamp and hook-like structures. These valves are known as sutureless heart valves. Examples of heart valve prostheses using sutureless fixations are shown in U.S. Pat. Nos. 3,143,742; 3,546,710; and 3,574,865. Replacement of the valve cannot be accomplished unless the valve structure is disassembled or the valve is removed with a portion of the heart tissue remaining attached to the valve structure.
The normal heart valve prosthesis must be reliable in use over an extended period of time. The valving member of a functioning heart valve prosthesis completes 40 million cycles in each year of operation. After a period of time, many heart valve prostheses malfunction and must be replaced with a new heart valve prosthesis. Changes in the condition of the patient and heart of the patient may require a new heart valve prosthesis or a heart valve prosthesis of a different design. It may be desirable that a new heart valve prosthesis of a new design be used in lieu of a heart valve prosthesis operating in the heart.